Merge pull request #39099 from teto/qemu_agent

qemu-guest-agent: init module

nixos/modules/module-list.nix

@@ -780,6 +780,7 @@
   ./virtualisation/hyperv-guest.nix
   ./virtualisation/openvswitch.nix
   ./virtualisation/parallels-guest.nix
+  ./virtualisation/qemu-guest-agent.nix
   ./virtualisation/rkt.nix
   ./virtualisation/virtualbox-guest.nix
   ./virtualisation/virtualbox-host.nix

nixos/modules/virtualisation/qemu-guest-agent.nix

@@ -0,0 +1,36 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.qemuGuest;
+in {
+
+  options.services.qemuGuest = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Whether to enable the qemu guest agent.";
+      };
+  };
+
+  config = mkIf cfg.enable (
+      mkMerge [
+    {
+
+      services.udev.extraRules = ''
+        SUBSYSTEM=="virtio-ports", ATTR{name}=="org.qemu.guest_agent.0", TAG+="systemd" ENV{SYSTEMD_WANTS}="qemu-guest-agent.service"
+      '';
+
+      systemd.services.qemu-guest-agent = {
+        description = "Run the QEMU Guest Agent";
+        serviceConfig = {
+          ExecStart = "${pkgs.kvm.ga}/bin/qemu-ga";
+          Restart = "always";
+          RestartSec = 0;
+        };
+      };
+    }
+  ]
+  );
+}

nixos/modules/virtualisation/qemu-vm.nix

@@ -360,6 +360,15 @@ in
           type = types.enum [ "virtio" "scsi" "ide" ];
           description = "The interface used for the virtual hard disks.";
         };
+
+      guestAgent.enable =
+        mkOption {
+          default = true;
+          type = types.bool;
+          description = ''
+            Enable the Qemu guest agent.
+          '';
+        };
     };
 
     virtualisation.useBootLoader =
@@ -511,6 +520,8 @@ in
     # Don't run ntpd in the guest.  It should get the correct time from KVM.
     services.timesyncd.enable = false;
 
+    services.qemuGuest.enable = cfg.qemu.guestAgent.enable;
+
     system.build.vm = pkgs.runCommand "nixos-vm" { preferLocalBuild = true; }
       ''
         mkdir -p $out/bin